We propose the development of a completely wireless, "smart" surface electromyographic (EMG) system. The multi-channel digital system will provide reliable, accurate, and noninvasive monitoring of the neuromuscular system without encumbering the user with wires or body-worn hardware. The innovation is a significant departure from current state-of-the-art systems. Current technology severely constrains the usability and freedom of movement of recording EMG signals, particularly in children and in the many applications where it is not uncommon to record 8 or even 16 channels of such information. The Phase I prototype sensor will be completely re-designed to reduce its size and power requirements through the use of current state-of-the-art components. The sensor will function within a network of 8 units for extended monitoring periods. They will be encapsulated to withstand the demands of vigorous monitoring activities through implementation of innovations in detection surface geometry and sensor/skin interface. Programming of the sensor will enhance the "smart" features of the Phase I sensor and provide full-bandwidth raw EMG signals, processed amplitude parameters of the EMG signal, "on-off' EMG signal states, and onboard storage of calculated parameters for long term monitoring. The base station from Phase I will be enhanced to control the sensor network, receive the processed EMG signals from the sensors, make them available to a PC, and will support up to 8 sensors in a network that continuously acquires and transmits data. Sensor control will include such features as "start-stop" functions, configuration options, and power management. A graphical user interface will be provided to enable the researcher to operate the acquisition system, view the signals in real-time, and provide a conduit for analyzing data using existing software developed by the research team. The system will be evaluated among target populations of children and adults, including patients, during simulated and real-world applications in physical rehabilitation, ergonomics, and sports/exercise. Upon achieving the objectives of Phase II, the innovation will be at a stage of development that will prepare it for commercialization. The commercial possibilities for this system extend well beyond Nl/-I's immediate interests in rehabilitation, biomechanics, motor control, ergonomics, sports medicine, and sleep studies, to fields of space countermeasures (NASA), and monitoring of land warriors (DOD)